This relates generally to isolated DC-DC converters, and more particularly to efficient, high input and/or output voltage isolated DC-DC converters.
Isolated DC-DC converters typically include a transformer, with: (a) a power generating input side, typically called the primary side; and (b) a power output side, typically called the secondary side. The differences between an isolated converter and a non-isolated converter are that: (a) in an isolated converter, the primary side and the secondary side have different grounds; and (b) in a non-isolated converter, the primary side and the secondary side share a same ground (such as using an inductor, instead of a transformer, to convert voltage).
Isolated DC-DC converters can be small enough to fit within an integrated circuit (“IC”) package, but may require significant current on the primary side to drive the secondary side across the isolation barrier, i.e., the gap between the transformer coils. Such converters can be used for transferring power from a high voltage domain to a low voltage domain, such as from a power line to a set of consumer electronics, or from a battery on an electric vehicle to electronics on that vehicle. Grounds in high voltage regimes (e.g., the power line or battery) may have voltage swings (such as 1000V or 1500V swings), which the devices connecting to those grounds are designed to tolerate. Grounds in the low voltage regimes may have much smaller swings (such as much less than 1V), and devices connected to those low voltage grounds could be rendered inoperative if subjected to the voltage swings tolerated in a high voltage regime. Isolation barriers separate high voltage regimes from low voltage regimes, so that power transfer can be performed without damaging low voltage components.